1. Field of the Invention
This invention relates to a method and apparatus to facilitate viewing of a visual indicator obstructed by a surface-mount technology (SMT) connector, and particularly to a method and apparatus to facilitate viewing of a lamp obstructed by a SMT DIMM socket or other SMT connectors.
2. Description of Background
In computer systems such as personal computers, a socket is referred to as an electrical connector generally mounted on a motherboard (main board) in order to connect extension boards such as extended interface boards for peripheral devices or extended memory boards to the motherboard. The motherboard and extension boards may be electrically connected by plugging the extension boards into the electrical connector.
The structure of a common electrical connector will be described here with the example of an electrical connector, as illustrated in FIGS. 1 and 2, used to connect an extension memory module (hereinafter, “module”) referred to as a DIMM (dual in-line memory module). This module (not shown) corresponds to the extension board described above.
A dual in-line memory module (DIMM) is becoming more popular for use in the present PC industry, and thus uses a DIMM socket connector mounted on the motherboard for mechanical and electrical interconnect of the corresponding DIMM therein for signal transmission between the motherboard and the DIMM. A main feature of the typical DIMM connector as illustrated in FIGS. 1 and 2 is that the DIMM connector 10 includes generally a pair of ejector levers 12 at two opposite ends of a DIMM connector body 14 so that such DIMM may not only be properly retained in the DIMM connector body 14 without possibility of inadvertent withdrawal by vibration or external impact, but also easily ejected from the DIMM connector body 14 by rotational movement of the ejector lever 12.
Previous designs of the DIMM connector 10 were mechanically anchored to the PCB via the pin-through-hole or compliant pin nature of the PCB leads. With more of the industry moving to SMT (Surface Mount Technology) connectors due to PCB wiring density, path length, and electrical signal integrity concerns, new mechanical requirements emerge due to the delicate SMT interface, compared to the more mechanically robust compliant pin and pin-through-hole interfaces in previous applications. This disclosure addresses the present surface-mount design, which uses solder at the SMT joints and printed wiring board (PWB) solder pads.
The European Union has a directive referred to as RoHS (Reduction of Hazardous Substance), which mandates elimination of the use of lead in the solder for the present surface-mount design. However, the use of lead-free solder raises the processing temperature at which components are subjected to due to the higher melting point temperature of the lead-free solder. The higher melting point temperature can deform or even melt the plastic used to make the current DIMM ejector levers.
For example, certain DIMM socket connectors use clear plastic ejector levers. The clear plastic ejector levers function as light pipes, allowing service personnel to visually inspect activation of amber colored LEDs, which are often obstructed from plain view by an opaque ejector lever, as the LEDs are placed under or near the end of a DIMM socket connector. More specifically, many servers use fault LEDs next to DIMM socket connectors to visually indicate when there is a memory failure of a respective DIMM. However, the clear plastic used in these ejector levers does not stand up well to the increased RoHS soldering temperatures.
One solution to this problem includes assembling the clear plastic levers to the DIMM socket connector once the higher temperature soldering is completed. However, this solution requires significant reworking of manufacturing procedures to hand assemble the ejector levers onto the socket connectors. Furthermore, the tight clearances between adjacent socket connectors mounted to the PCB would make this operation difficult. Therefore, a different solution is still desired.